How to get the last day of month in postgres?

Question

How to find the last day os the month in postgres? I have a date columns stored as numeric(18) in the format(YYYYMMDD) I am trying it to make it date using

Answer 1

For future searches, Redshift does not accept INTERVAL '1 month'. Instead use dateadd(month, 1, date) as documented here.

To get the end of the month use: DATEADD(DAY, -1, (DATE_TRUNC('month', DATEADD(MONTH, 1, date))))

Answer 2

select to_char(date_trunc('month', now() + '01 Months'::interval) - '01 Days'::interval, 'YYYYmmDD'::text)::numeric as end_period_n

Answer 3

For anybody coming to this question looking for the Postgres way to do this (not using Redshift), here's how you'd do it:

SELECT (date_trunc('month', '2017-01-05'::date) + interval '1 month' - interval '1 day')::date
AS end_of_month;

Replacing the '2017-01-05' with whatever date you want to use. You can make this into a function like this:

create function end_of_month(date)
returns date as
$$
select (date_trunc('month', $1) + interval '1 month' - interval '1 day')::date;
$$ language 'sql'
immutable strict;

Answer 4

Okay, so you've got a numeric(18) column containing numbers like 20150118. You can convert that to a date like:

to_date(your_date_column::text, 'YYYYMMDD')

From a date, you can grab the last day of the month like:

(date_trunc('month', your_date_column) + 
    interval '1 month' - interval '1 day')::date;

Combined, you'd get:

select  (date_trunc('month', to_date(act_dt::text, 'YYYYMMDD')) + 
           interval '1 month' - interval '1 day')::date
from    YourTable;

Example at SQL Fiddle.

Answer 5

Simply by using the last_day function:

select last_day(to_date(act_date,'YYYYMMDD'))

PS: Now, i believe that you know that it is very important to choose the right tags for your own question!